Conventionally, messages sent from untrusted clients over untrusted networks can be easily eavesdropped by middlemen. These messages may contain sensitive information that can be compromised through their interception by malicious parties. The sensitive information may be used by a malicious party to gain unauthorized access to a resource. For example, a password may be intercepted by a malicious party and used to gain access to personal information.
Oftentimes, messages are sent over untrusted networks because they are well-established and easy to use. For example, a user may send personal information through e-mail, social networking, or other popular channels. Such a user may not realize that many network-based communications offer little protection against eavesdropping and interception. Some users that do realize the risks associated with network-based communications choose nevertheless to use such insecure communications due to the difficulties of using secure methods. In other words, some users believe that the cost, effort and/or technological expertise required to use more secure methods outweigh the benefits of being certain that the message is not compromised.
Thus, unauthorized access to messages during transmission across a network presents significant concerns. These concerns have been attempted to be addressed by various secure transmission techniques. For example, Secure Sockets Layer (SSL) is a security technology that establishes an encrypted link between a web server and a browser, ensuring that data passed between the web server are browser remain private. As another example, Hypertext Transfer Protocol Secure (HTTPS) is a protocol for secure communication over a network within a connection encrypted by SSL. HTTPS provides authentication of a website and its associated web server, as well as bidirectional encryption of communications between the web server and a browser, using SSL.
However, neither of these techniques provide sufficient protection against malicious middlemen. Conventional browser systems may explicitly trust multiple Certificate Authorities, which can be leveraged by both legitimate middlemen (e.g., content delivery networks, data less prevention systems, accelerators, etc.) and malicious middlemen (e.g., fake WiFi hotspots, DNS poisoning systems, etc.). These middlemen can conventionally access the payloads within SSL connections without detection. Thus, malicious middlemen may gain access to apparently secured messages. In addition, legitimate middlemen may themselves become the targets of malicious attacks, again compromising the apparently secure original messages.